Electrical system tester



FIG. 1 is a perspective view of an electrical system tester depicting a new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is an opposite side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken line portion of the figure drawings is included to show unclaimed subject matter only and forms no part of the claimed design. 

CLAIM The ornamental design for an electrical system tester, as shown and described. 